1. Field of the invention
The present invention concerns a bolt-cutter type cutting tool.
2. Description of the prior art
Many bolt-cutter type cutting tools are known in themselves. In a manner that is known in itself, a tool of this kind comprises two blade supports each of which is mounted to pivot about a respective pin carried by at least one spacer member of the tool and carries at the free end of its inside edge a removable cutting blade having an interior cutting edge facing the interior cutting edge of the other cutting blade, the tool further including means for pivoting the two blade supports about their respective pivot pins in opposite directions so as to move the two cutting edges towards each other in order to cut a metal member such as a bolt.
To enable it to withstand the forces that are generated during cutting, each blade support is forged and then subjected to appropriate heat treatment. The unit cost of a blade support of this kind is therefore high. The removable cutting blade may be made from a costly noble material, such as high speed steel or tungsten carbide, for example. In one embodiment known in itself the blade has a substantially triangular cross-section and can be fixed to the support by each of its faces in succession to enable the use of the opposite cutting edge. The blade is fixed to its support by devices such as claws which may constitute a weakness of the tool.
In an embodiment that is less costly but offers a lower level of performance, the blade is in one piece with the blade support which is forged and then quenched. The cutting edge is straightened, for example, in order to penetrate better into the metal to be cut and is subjected to a medium-frequency second quench to impart a very high hardness to the cutting surface.
In all cases, the manufacture of the blade support by forging, various heat treatments and quenching is very costly.
The aim of the present invention is to remedy the drawbacks of prior art bolt-cutters and propose a cutting tool of the aforementioned type having a structure that enables it to be manufactured and assembled in a particular economical way that can be used both for a relatively low cost tool of moderate quality and for a more costly high-performance and reliable tool.